Transcript of "Diabetes and pregnancy"

1.
FUEL METABOLISM IN DIABETIC
PREGNANCY
The effect of diabetic pregnancy on fuel metabolism
is one of underutilization of exogenous fuel in the fed
state (facilitated anabolism reduced) and over-
production from endogenous source in the fasted state
(hyperaccelerated starvation). The first sign of preg-
nancy in a diabetic (particularly in type 1 diabetes) as
early as the first week of gestation and even before
nausea or vomiting sets in may be early morning fasting
ketonuria. A minor proportion of women lack the
necessary B-cell reserve to maintain euglycemia during
pregnancy, and develop impaired glucose tolerance
(IGT). They have significantly lower insulin responses
at 30 and 60 min after oral glucose load compared with
glucose-tolerant controls (1), while insulin sensitivity
is similarly reduced in the second trimester (1,2). The
C-peptide response to intravenous glucagon is also
significantly reduced in women with IGT in pregnancy
(3), while serum proinsulin concentrations are
increased (4). The need for insulin treatment in
gestational diabetes mellitus (GDM) is associated with
raised circulating proinsulin levels, implying that
greater B-cell dysfuction leads to worse glucose
intolerance (5). IGT in pregnancy can vary in severity
but even mild degrees are accompanied by other
disturbances, including abnormalities of glycerol and
nonesterified fatty acid metabolism (6). Women with a
previous history of GDM who become glucose-tolerant
postpartum show continuing B-cell dysfunction,
characterized by impaired insulin release in response to
oral glucose, and impaired lipolysis despite normal
insulin sensitivity (7,8). This points to a decreased B-
cell function in GDM women, which makes them
susceptible to the future development of type 2
diabetes (9). Carbohydrate intolerance deteriorates
early in pregnancy in diabetic women, in parallel with
the physiological decrease in insulin sensitivity. Women
with type 1 diabetes are dependent on increased
insulin dosage to maintain glycemic control. On an
average, lasting from 12th week to 37 weeks of
gestation, they may require weekly increments of 6% of
insulin dosage from their preconceptional dose. Late
pregnancy is associated with a threefold incidence of
newly presenting type 1 diabetes (c.f. type 2
gestational diabetes) (10). This may occur because the
insulin resistance of pregnancy imposes an additional
burden on the beta cells of women who are in the
prolonged but subclinical stage of ’prediabetes’ with
active insulinitis but enough residual B-cell mass to
prevent overt hyperglycemia beyond pregnancy.
Maternal diabetes also affects the placenta, both
structurally and functionally. The placental glycogen
content and insulin-binding capacity are higher in
pregestational diabetic than in nondiabetic pregnancies
(11).
Pregnancy-induced lipolysis makes women with type
1 diabetes more susceptible to diabetic ketoacidosis. It
131Diabetologia Croatica 31-3, 2002
1 EVSM Nursing Home,
Inkollu - 523167, Prakasam Dist,
Andhra Pradesh, India
2 Vuk Vrhovac Institute, University Clinic for Diabetes,
Endocrinology and Metabolic Diseases,
Dugi dol 4a, HR-10000 Zagreb, Croatia
Review
DIABETES AND PREGNANCY
Eadara Krishna Murthy1, Ivana Pavliæ-Renar2, @eljko Metelko2

2.
may develop quickly and with relatively mild
hyperglycemia (12). If left untreated, it may cause fetal
death (13).
The mother with type 2 diabetes also has to increase
her insulin production to counteract the pregnancy
related insulin resistance. Before pregnancy these
women have already had decreased insulin sensitivity.
Further demands on their compromised beta cell
function cause in most diet-treated type 2 women to
require insulin (or oral agents, in those parts of the
world where insulin is not available) early in pregnancy.
CLASSIFICATION OF DIABETES IN
PREGNANCY
A uniform classification of diabetic pregnancies is still
needed for both epidemiological and clinical purposes.
Both the World Health Organization (WHO) (14) and
the National Diabetes Data Group (NDDG) (15) of
the National Institutes of Health (NIH) have endorsed
a classification based on the etiology. WHO
classification differs only by recognizing IGT before
pregnancy. This is simple but of no prognostic value.
Classification of maternal diabetes in pregnancy:
• Pregestational diabetes: pre-existing type 1 or type 2
or secondary
• Gestational diabetes: diagnosis is made post-
gestationally; normal glucose tolerance
• Any type of diabetes mellitus occurring first in
pregnancy
Pregestational diabetes mellitus
This term denotes an already established diabetic
marching through pregnancy. It has been long known
that the incidence of maternal and fetal complications
are greatly influenced by the severity of maternal
diabetes. On assessing the severity, the following
factors have to be taken into consideration: duration of
diabetes, maternal age at the onset of diabetes,
presence or absence of vascular complications, and
methods of treatment. On the basis of preconceptional
factors, Priscilla White established a clinical
classification method in 1949 (16) and subsequently
modified it in 1965 and 1971. This classification
attempted to predict the outcome of pregnancy
according to various metabolic, obstetric and other risk
factors, and graded the prognosis from A (best) to F
(worst). Subsequently, attempts to update the
classification and incorporate ischemic heart disease
and renal transplantation (17) have rendered it too
cumbersome for general use.
Another system of classification using the
prognostically unfavorable signs in pregnancy is based
on the risk factors encountered during the pregnancy
itself (18). These are toxemia, clinically manifested
pyelonephritis, severe acidosis, lack of patient
cooperation, and markedly unfavorable social
conditions. A combination of these two classifications
predicts fetal outcome more accurately (19), however,
their complexity has made them obsolete.
Most European centers apply White classification
modified by Pedersen (20) (Table 1):
Table 1. White’s classification of diabetes during
pregnancy
Class A Diet alone sufficient, any duration or age at onset
Class B Age at onset ≥20 years and duration <10 years
Class C Age at onset 10-19 years or duration 10-19 years
Class D Age at onset <10 years or duration ≥20 years or
background retinopathy or hypertension (not
preeclampsia)
Class R Proliferative retinopathy or vitreous hemorrhage
Class F Nephropathy with proteinuria >500 mg/day
Class RF Criteria for both R and F classes coexist
Class H Arteriosclerotic heart disease clinically evident
Class T Prior renal transplantation
Note: Women in classes below A require insulin therapy. Women in R, F,
RF, H and T classes have no criteria for age at diabetes onset or duration
of diabetes but usually have long-term diabetes. The development of
complication moves the patient to the next class.
• White’s group A: Diabetes existing prior to or
detected during pregnancy, needing only diet, no
insulin treatment being necessary.
• White’s group A/B: Diabetes appearing before or
during pregnancy, insulin treatment becoming
necessary during pregnancy.
• White’s group B: Diabetes pre-existing and
necessitating insulin treatment before conception,
onset of diabetes after maternal age of 20 years,
and/or duration of diabetes shorter than 10 years.
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• White’s group C: Duration of 10-19 years and/or
onset of diabetes between 10-19 years of maternal
age, insulin dependent diabetes. (These four groups
are characterized by the absence of diabetic
angiopathy).
• White’s group D: Onset of insulin dependent
diabetes before the age of 10 years and/or duration
exceeding 20 years. All pregnant mothers with
discernible but not proliferative diabetic retinopathy
are classified as group D.
• White’s group F: Severe proliferative diabetic
retinopathy and/or diabetic nephropathy before or
during pregnancy.
CONSEQUENCES OF THE CHANGES IN
FUEL METABOLISM DURING DIABETIC
PREGNANCY
If hyperglycemia is present during the first trimester
of pregnancy when organogenesis is taking place,
congenital malformations may occur. The incidence is
said to be as high as 8% in uncomplicated diabetic
pregnancies (uncontrolled during the first 8 weeks of
pregnancy), which is two- to threefold that in the
general population (21). The malformations often
involve the heart and central nervous system, and are
potentially lethal. Apart from congenital anomalies,
there can be fetal loss through early spontaneous
abortion (22). In contrary to the earlier belief that
maternal hypoglycemia is an early gestational cause of
disturbed organogenesis, Pedersen found a significant
negative correlation between the incidence of
congenital malformations and that of severe
hypoglycemia occurring during the first trimester of
pregnancy (23). In addition to maternal hypoglycemia,
several other factors may be involved in the etiology of
malformations due to maternal diabetes (23). The role
of other factors has been demonstrated in animal
experiments of maternal ketonemia (24), fetal zinc
depletion (25), and inhibited somatomedin action
(26). The role of genetically determined susceptibility
needs further elucidation. It seems probable that the
high incidence of malformations in newborns of
diabetic mothers is multifactorial in origin. The
malformations develop in the genetically susceptible
individuals as the result of a number of teratogenic
factors (23). Fetal complications are classified
according to the trimester of pregnancy in a poorly
controlled diabetic (Table 2).
Hyperglycemia during second trimester may cause
impairment of intellectual performance in the
offspring. The fetal pancreas is capable of secreting
insulin by 8th to 11th week of gestation. Maternal
glucose that crosses the placenta stimulates beta cells,
and mixed nutrients would have similar effects
(modified Pedersen’s hypothesis) (Fig 1).
Consequently, the fetal beta cell activity depends on
the maternal blood glucose and amino acid level. Once
stimulated, the fetal pancreas continues to secrete
insulin in an autonomus fashion regardless of glucose
stimulation. Maternal glucose and fetal hyper-
insulinemia result in macrosomia (weight >4 kg) and
hypokalemia, the latter producing fatal cardiac
arrhythmias. Unexplained intrauterine death in the
third trimester, although rare, may be due to fetal
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retsemirttsriF retsemirtdnoceS retsemirtdrihT
snoitamroflaM
htworG
noitadrater
egatsawlateF
cihportrepyH
yhtapoymoidrac
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aimerhtyrE
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Table 2. Fetal problems associated with maternal
hyperglycemia according to trimesters of gestation
MATERNAL PLACENTAL FETAL
Insulin release Birth weight
Lipid Glycogen
Glucose utilization
Insulin
(Hyperinsulinemia)
Hyperglycemia Hyperglycemia
Figure 1. Result of maternal hyperglycemia modified
Pedersen's hypothesis

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hypoxia (placental insufficiency). This life threatening
metabolic state could be prevented by maintaining
maternal euglycemia throughout the period of
gestation.
Hypoglycemia
Due to endogenous hyperinsulinemia and suppres-
sion of endogenous glucose production, the infant of a
diabetic mother (IDM) is at an increased risk of
hypoglycemia at 1 to 3 hours after birth. The factor
mainly protective against fetal hypoglycemia is optimal
control of maternal hypoglycemia, especially during the
third trimester and during labor. It has been shown that
a mean maternal plasma glucose >6 mmol/L during the
last four hours in a diabetic mother leads to a higher
incidence of neonatal hypoglycemia.
Hypocalcemia
About 25% of IDMs may present with serum calcium
<7 mg/dl, and this may remain mostly asymptomatic
and is usually detectable during the second and third
day of birth. Asphyxia and prematurity, operating
through elevated cortisol, induce vitamin D
antagonism at the intestinal level.
Respiratory distress and fetal metabolic acidosis may
result in calcium being shifted from intracellular to
extracellular pools, and reversal of this shift during
correction of the acidotic event may produce
hypocalcemia. Hypomagnesemia may coexist and may
require correction.
Respiratory distress syndrome (RDS)
The incidence is six-fold for any given gestational age
compared with nondiabetic pregnancies (27). It is
thought to be due to poor diabetic control (28), which
interferes with the production of the surfactant
resulting in hyaline membrane disease of fetal lungs. It
is postulated that fetal hyperinsulinemia inhibits the
synthesis of the surfactant phospholipid component
(29), although this theory is not universally accepted.
Polycythemia
It is relatively common in IDM and is mostly due to
the hypoxic stimulus by the placental insufficiency and
elevated glycohemoglobin. Overtransfusion from a
large placenta of diabetic pregnancy may also
contribute. The resultant hyperviscosity may induce
congestive heart failure and vascular thrombosis
accounting for the increased risk of renal vein
thrombosis in these infants.
Hyperbilirubinemia
This common abnormality is due to the increased
bilirubin production and increased life span of the
RBCs with glycosylated cell membranes. Hepatic
conjugation of bilirubin may be impaired due to an
immature liver.
Macrosomia
The infant of a diabetic mother is often large for
gestational age (LGA) (growth promoted) due to
increased maternal-fetal nutrient transfer (30).
Abnormalities include excessive abdominal fat
deposition, organomegaly (notably of the liver, spleen
and heart), and accelerated skeletal maturation. The
basis of LGA infants in diabetic pregnancies is fetal
hyperinsulinemia (31).
Stillbirth in diabetic pregnancy
Historically diabetic pregnancies often terminated in
late unexpected intrauterine death. The exact cause is
still unknown. The theories implicated include fetal
hypoxia and acidosis (32), and hypokalemia leading to
dysrhythmias, and placental dysfunction and
competition for essential nutrients (33-35).
GESTATIONAL DIABETES MELLITUS
Definition
Gestational diabetes mellitus (GDM) is defined as
any degree of glucose intolerance with onset or first
recognition during pregnancy (36). The definition
applies whether insulin or only diet modification is
used for treatment, and whether or not the condition
persists after pregnancy. It does not exclude the
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possibility that unrecognized glucose intolerance may
have antedated or begun concomitantly with the
pregnancy.
Approximately 7% of all pregnancies are complicated
by GDM, resulting in more than 200,000 cases
annually. The prevalence may range from 1% to 14% of
all pregnancies, depending on the population studied
and the diagnostic tests employed.
Detection and diagnosis
Risk assessment for GDM should be undertaken at
the first parental visit. Women with clinical
characteristics consistent with a high risk of GDM
should undergo glucose testing as soon as feasible. If
they are found not to have GDM at that initial
screening, they should be retested between 24 and 28
weeks of gestation. Women at an average risk should
have testing undertaken at 24-28 weeks of gestation.
High risk patients
• GDM during previous pregnancy
• Diabetes in a first degree relative
• High weight babies born from a previous pregnancy
• The baby born from a previous pregnancy showing
any complications known to be associated as arising
from maternal GDM
• A history of stillbirth or infants with congenital
abnormalities
• Poor obstetric history including recurrent fetal
wastage, hypertension, eclampsia, hydramnios, etc.
• A history of repeated or persistent urinary tract
infection
• Glycosuria manifesting during pregnancy
• Age >30 years
However, screening using clinical risk factors fails to
diagnose one third to one half of patients with GDM
(37,38). Low-risk status requires no glucose testing but
this category is limited to those women meeting all of
the following characteristics:
• age<25 years
• weight normal before pregnancy
• member of an ethnic group with a low prevalence of
GDM
• no known diabetes in first-degree relatives
• no history of abnormal glucose tolerance
• no history of poor obstetric outcome
A fasting plasma glucose level >126 mg/dl (7.0
mmol/L) or a casual plasma glucose >200 mg/dl (11.1
mmol/L) meets the threshold for the diagnosis of
diabetes if confirmed on a subsequent day, and
precludes the need of any glucose challenge. In the
absence of this degree of hyperglycemia, evaluation for
GDM in women with average or high-risk characte-
ristics should follow one of two approaches.
• One-step approach: diagnostic oral glucose tolerance
test (OGTT) without prior plasma or serum glucose
screening. The one-step approach may be cost-
effective in high-risk patients or population (e.g.,
some native-American groups).
• Two-step approach: initial screening by measuring
plasma or serum glucose concentration 1 hour after a
50-g oral glucose load (glucose challenge test
(GCT)) and a diagnostic OGTT in the subset of
women exceeding the glucose threshold value on
GCT. When the two-step approach is employed, a
glucose threshold value >140 mg/dl (7.8 mmol/l)
identifies approximately 80% of women with GDM,
and the yield is further increased to 90% by using a
cutoff of >130 mg/dl (7.2 mmol/l).
With either approach, the diagnosis of GDM is based
on OGTT. Diagnostic criteria for the 100-g OGTT are
derived from the original work of O’Sullivan and
Mahan, modified by Carpenter and Coustan, and are
shown in Table 3. Alternatively, the diagnosis can be
made using a 75-g glucose load and the glucose
135Diabetologia Croatica 31-3, 2002
E. Krishna Murthy, I.Pavliæ-Renar, @. Metelko / DIABETES AND PREGNANCY
Table 3. Diagnosis of GDM with 100-g oral glucose
load
ld/gm l/lomm
gnitsaF 59 3.5
h-1 081 0.01
h-2 551 6.8
h-3 041 8.7
Table 4. Diagnosis of GDM with 75-g oral glucose load
ld/gm l/lomm
gnitsaF 59 3.5
h-1 081 0.01
h-2 551 6.8

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threshold value listed for fasting, 1 h, and 2 h (Table
4); however, this test is not as well validated for
detection of at-risk infants or mothers as the 100-g
OGTT.
Two or more of venous plasma concentrations must be
met or exceeded for a positive diagnosis. The test
should be done in the morning after an overnight fast
of 8 to 14 h and after at least 3 days of unrestricted diet
(>150 g carbohydrate per day) and unlimited physical
activity. The subject should remain seated and should
not smoke throughout the test.
The American Diabetes Association (ADA) and WHO
diagnostic criteria for GDM were evaluated against
pregnancy outcomes. The cohort study consecutively
enrolled Brazilian adult females attending general
prenatal clinics. All women were requested to
undertake a standardized 2-h 75-g OGTT between
their estimated 24th and 28th week of gestation and
were then followed until delivery.
GDM based on a 2-h 75-g OGTT as defined by either
WHO or ADA criteria was found to predict adverse
pregnancy outcomes.
OBSTETRIC AND PERINATAL
CONSIDERATIONS
The presence of fasting hyperglycemia (>105 mg/dl
or >5.8 mmol/l) may be associated with an increase in
the risk of intrauterine fetal death during the last 4-8
weeks of gestation. GDM of any severity increases the
risk of fetal macrosomia. Neonatal hypoglycemia,
jaundice, polycythemia and hypocalcemia may
complicate GDM as well. GDM is associated with an
increased frequency of maternal hypertensive disorders
and the need of cesarean section.
Long-term impact of GDM on maternal health
Women with GDM are at an increased risk of the
development of diabetes, usually type 2, after
pregnancy. Obesity and other factors that promote
insulin resistance appear to enhance the risk of type 2
diabetes after GDM, while markers of islet cell-
directed autoimmunity are associated with an increase
in the risk of type 1 diabetes. The offspring of women
with GDM are at an increased risk of obesity, glucose
intolerance and diabetes in late adolescence and young
adulthood. Approximately 5% - 10% of women with
GDM subsequently develop type 1 diabetes (39).
Women with GDM have an increased lifetime risk of
developing diabetes, being over 30% compared with
10% in normal controls at 16 years after the index
pregnancy (40). The requirements of insulin in
pregnancy, obesity and further weight gain postpartum
are also associated with an increased risk of future
diabetes, mostly type 2 (8,41). Other predictors are
family history of type 2 diabetes, further pregnancies
(42), and a relatively impaired response to oral glucose.
It is appropriate to target women who have had GDM
with health education to reduce cardiovascular risk
factors, as the morbidity and mortality from premature
heart disease is markedly increased in diabetic women
(43). The importance of weight maintenance and
exercise should be stressed, both for cardiovascular
protection and for delaying the onset of IGT and type
2 diabetes (44,45).
Monitoring fetal well-being
Fetal heart rate monitoring by cardiotocography is
advised. An unreactive (abnormal) non-stress
cardiotocogram (i.e. absence of accelerations of fetal
heart) may warrant urgent delivery. In many centers, a
biophysical score (BPS) is obtained when non-stress
test (NST) is nonreactive. There are five components
to BPS, all being given a score 2 if present and score 0
if absent. A total score of 8 or 10 is considered
reassuring of fetal health, a score of 6 is considered
equivocal, and resting should be done within 24 h. A
score 4 or less is abnormal (46) (Table 5).
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E. Krishna Murthy, I.Pavliæ-Renar, @. Metelko / DIABETES AND PREGNANCY
Table 5. Biophysical profile score
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Autonomic neuropathy is usually accompanied by
peripheral neuropathic disturbances. This condition
can be diagnosed by conducting cardiovascular reflexes.
The loss of sweating may precede abnormal
cardiovascular tests.
Assessment of fetal maturity
Respiratory distress syndrome (RDS) has been a
major cause of neonatal morbidity and mortality in
diabetic pregnancies. Amniocentesis is done to assess
pulmonary maturity by assessing the lecithin to
sphingomyelin (L:S) ratio. If it is less than 2:1,
prophylactic steroids are given to accelerate lung
maturity (27).
MATERNAL COMPLICATIONS
Preeclampsia
It is more common than in non-diabetic pregnancies
(10% vs. 4%) and increases to 30% in the presence of
vascular disease (47). In women without pre-existing
hypertension or nephropathy, preeclampsia becomes
apparent when the classical signs of hypertension and
proteinuria develop. At this time, the only curative
treatment is delivery of the baby. In women with
nephropathy in whom the diagnosis is unclear, delivery
is usually indicated when renal function deteriorates
and blood pressure becomes difficult to control, or if
fetal compromise occurs.
Preterm labor
The most common cause is still iatrogenic for the
management of preeclampsia (9%). Spontaneous
rupture of membranes (6%) and spontaneous onset of
labor (3%) possibly due to polyhydramnios also
contribute to this high incidence (48). Conventional
management of preterm labor in the absence of
obstetric contraindications is with an intravenous
infusion of beta-adrenergic agonist such as salbutamol
or ritodrine, which inhibit uterine contractivity, usually
given for 24 h. This is combined with high dose
glucocorticoids (typically two doses of 12 mg
dexamethasone given intramuscularly at 12 h apart) to
encourage fetal lung maturation. The two doses of
dexamethasone are repeated at weekly intervals while
the risk of preterm delivery remains.
Management of pregestational and gestational
diabetes mellitus
An important predictor of fetal outcome either in
pregestational or gestational diabetes is the glycemic
control attained immediately before and during
pregnancy. Complications for the mother or baby may
arise from medical, obstetric or neonatal factors. Thus,
a management team consisting of a diabetologist, an
obstetrician, a pediatrician, a nurse educator, a dietitian
and a social worker continues to be essential to achieve
this goal.
Pregestational diabetes type 1 and type 2
All premenopausal diabetic women should be
considered as potential mothers, and should be given
contraceptive and pregnancy advice in the routine
diabetic clinic. Once a woman expresses an interest in
becoming pregnant, she should have access to the
diabetic antenatal clinic for specific preconceptional
advice. Any woman planning a pregnancy should take a
folate-rich diet together with 400 µg folic acid daily
from before conception until the 12th week of gestation
to reduce the risk of neural tube defects. In view of the
association of diabetic pregnancy with spina bifida and
other neural tube malformations, it also seems sensible
to treat diabetic women with high-dose folic acid. In
addition, rubella immunity should be assessed, as
should be sickle-cell or thalassemia carrier status in
women from relevant ethnic groups, and the women’s
partners should be tested if she is a carrier. A young
woman should be instructed on how to self-assess her
diabetic status and achieve normoglycemia. Whenever
possible this should be done before conception,
otherwise as soon as pregnancy is confirmed, and
maintained thereafter. The patient should be reassured
of the pregnancy and diabetes being incompatible. She
should be assured that vaginal delivery close to term is
likely and that the baby will be normal and healthy. A
multidisciplinary team should be formed, along with
active participation of the mother and her family.
Education about special issues related to pregnancy
should begin at the time when a diabetic wants to
conceive. Pregnancy should not be discouraged on
genetic grounds. The patient must be informed about
the risk of perinatal mortality, congenital anomalies,
maternal mortality, diabetic complications in
pregnancy, obstetric complications, inheritance of
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diabetes in offspring, etc. She must be advised to come
for frequent antenatal visits, strict glycemic control
(through home blood glucose monitoring and
optimized insulin regimen), to stop smoking and
drinking alcohol, and to stick to the appropriate diet.
All women with type 2 diabetes should switch to
insulin, ideally before pregnancy or early in the first
trimester, to achieve good glycemic control. Moreover,
the oral hypoglycemic drugs cross the placenta and are
thought to be potentially teratogenic. They also
stimulate fetal beta cells directly, aggravating fetal
hyperinsulinemia and macrosomia. Diabetic women
with established nephropathy should be advised
against pregnancy, since it can increase the risk for both
the mother and the offspring (44). Patients with active
proliferative retinopathy must postpone pregnancy
until they will have undergone photocoagulation
therapy.
Ischemic heart disease demands treatment prior to
any decision about pregnancy. Myocardial infarction
occurring during pregnancy carries a high mortality rate
for both the mother and the fetus (49).
MANAGEMENT DURING PREGNANCY
Diet
There is no need to make fundamental changes to the
diabetic diet because of pregnancy. Carbohydrate, fat
and proteins are taken in appropriate proportions. It is
important to avoid excessive dietary protein in women
with nephropathy. The expected weight gain during
pregnancy is 300 to 400 g per week and total weight
gain is 10 to 12 kg by term. The diet schedule must be
planned in such a way as to prevent postprandial
hyperglycemia. Diabetic fetopathy which is the result
of maternal postprandial hyperglycemia can be
minimized when the peak postprandial response is
blunted. Gestational diabetes is a disease of
carbohydrate intolerance. Thus, the peak postprandial
response is minimized in a woman with gestational
diabetes if her meal plan is carbohydrate restricted. A
caloric prescription therefore can be designed so as to
achieve postprandial normoglycemia by minimizing
carbohydrates in the meal plan. One diet that has been
proved to provide the needs of pregnancy and not to
result in excessive weight gain or hyperglycemia
consists of 30 kcal/kg of present pregnant weight for
normal weight women, 24 kcal/kg for overweight
women, and 12 kcal/kg for morbidly obese women
(50,51). Thus, the optimal diet for the gestational
diabetic women is based on maternal glucose as a
variable on which the success or failure of a dietary
prescription is based. Approximately 30 to 40 kcal/kg
ideal body weight or an increment of 300 kcal/day
above the basal requirement are needed. Those who
are not gaining weight as expected, particularly in the
third trimester, require admission to ensure adequate
nutrition to prevent low birth weight infants. Folic
acid, 400 µg/day, is given from before conception till 12
weeks of gestation to prevent neural tube defects (52).
MANAGEMENT DURING FIRST
TRIMESTER
All patients should be on insulin therapy. The women
whose glycemia is not under control should be
hospitalized till they achieve good glycemia. Patients
should be screened for hypertension and heart disease.
Additional investigations should include urine test for
protein, serum creatinine, and glycated hemoglobin
measurement to find the risk for congenital anomaly.
All other routine investigations like blood group, Hb%,
etc. should be done. Follow-up is generally at 2-4 weeks
at this step, depending on diabetic control and
presence of complications.
Ultrasound scan
Early ultrasound scan is important to estimate
gestational age because of the risk of preterm delivery
and because of macrosomia in the second trimester,
which may make later dating less accurate. Also, early
growth delay has been reported to be associated with a
sevenfold incidence of congenital abnormalities (53).
Early ultrasound is also important to detect gross
congenital anomalies such as anencephaly, unexpected
missed abortion, and multiple pregnancy.
Risk of miscarriage
The risk of miscarriage is higher with poor glycemic
control than in those with good glycemic control (9%
vs. 29%), insulin treatment and glucose monitoring
(54). It is appropriate to tend to a mean blood glucose
concentration between 5.6 and 6.7 mmol/L (55). All
patients have to monitor blood glucose at home four
times a day. The emphasis is on minimizing
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9.
postprandial peaks of glucose (to keep it below 7
mmol/L) and fasting level to below 5 mmol/L. To
achieve this, virtually all women need shortacting
insulin before each meal and an intermediate acting
insulin at bed time. For many women insulin
requirements do not begin to increase until second
trimester, and some women need to reduce it in the
first three months (56). An important family member
should be instructed how to treat hypoglycemia at
home.
MANAGEMENT DURING SECOND
TRIMESTER
Monitoring diabetic control
Insulin requirements will often have doubled by the
end of second trimester. The most problematic period
of the day is between breakfast and lunch, because of
the physiological tendency to hyperglycemia at this
time. The morning dose of shortacting insulin is
generally increased with careful adjustment of timing
of meal, so to avoid hypoglycemia. Diabetic
ketoacidosis occurs in up to 10% of pregnancies (57),
often with relatively mild hyperglycemia. So, urine
testing for ketones must be done in times of poor
glycemic control or intercurrent infection.
Monitoring diabetic complications
Vascular, renal and retinal problems need to be
followed carefully and appropriate treatment should be
undertaken. Hypertension should be managed with
drugs considered safe in pregnancy, usually
methyldopa, and nifedipine if a second agent is
required.
Monitoring the fetus
Detailed ultrasound scan has to be performed at 18-
20 weeks to rule out structural abnormalities of the
spine, skull, kidneys and heart. From 26 weeks
onwards, scans are done to assess fetal growth as it may
become apparent during this trimester.
Screening for chromosomal abnormalies
Diagnostic amniocentesis can be done to rule out
neural tube defects. The test is unreliable. So, most
centers depend on detailed ultrasound scanning.
Ultrasound measurement of fetal nuchal translucency
at 10-14 weeks of gestation may provide additional
information regarding the role of chromosomal anomaly
(58).
General review of obstetric progress
Most obstetric problems associated with diabetes,
such as preeclampsia, polyhydramnios, preterm labor,
macrosomia or growth retardation, and unexpected
intrauterine death occur in third trimester, however,
general surveillance for these factors is performed from
26 weeks of gestation.
MANAGEMENT DURING THIRD
TRIMESTER
Monitoring diabetic control
Insulin requirements become stable or may even
slightly decline at 34-36 weeks of gestation. Frequent
ultrasound scan should be performed to assess fetal
growth and liquor volume. Babies weighing more than
4000 g are said to be macrosomic, however, there may
be variation of +20% of the actual weight in ultrasound
formulas. So, birth weight can vary between 3200 g and
4800 g (59). Good glycemic control can reduce
macrosomia in babies. Macrosomia is often of concern
because of shoulder dystocia, which can lead to birth
injury or even to fetal death. Presently there is no fully
reliable way to predict which fetus will develop
shoulder dystocia and which will not. Polyhydramnios
may be detected at this time by ultrasound. It may be
related to fetal polyuria secondary to fetal
hyperglycemia (60). It may be associated with preterm
labor, premature rupture of membranes, unstable lie,
and cord prolapse. It is also associated with an
increased risk of stillbirth in diabetic women (61).
Nonsteroidal anti-inflammatory drugs such as
indomethacin have been used to reduce fetal urine
production, and consequently liquor volume tightening
of diabetic control may also be helpful in some cases.
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10.
Timing of delivery
Delivery is advised at 38 weeks of gestation (62),
while others allow the women with uncomplicated
diabetes to go into spontaneous labor irrespective of
the gestational age (63). In Murphy’s retrospective
review (63), 64% of 45 women went into spontaneous
labor after 37 weeks of gestation, with a mean gestation
of 39 weeks. All authors agree that pregnancy could
terminate before 40 weeks of gestation.
Uncomplicated diabetic pregnant women are allowed
for spontaneous delivery by some practitioners. The
patient has to be hospitalized during the last weeks of
pregnancy. Before inducing labor with oxytocin and
amniotomy, it is important to check uterine cervix
which has to be ripe. When cervix is not ripe, labor is
finished by cesarean section. Elective cesarean section
is rare except in breech presentation, placenta previa,
and other obstetric complications or fetal distress.
MANAGEMENT DURING DELIVERY AND
PUERPERIUM
Pregestational diabetes
During spontaneous or induced labor, the objectives
of medical management are to maintain plasma glucose
within the physiologic range (3.9 to 6.7 mmol/L) and to
prevent ketosis. Intravenous glucose is administered at
5 to 10 g/h by a constant infusion pump. All other
intravenous fluids are devoid of glucose. Patients with
type 2 diabetes often do not require insulin with this
regimen. Those with type 1 diabetes are treated with
small doses of subcutaneous regular insulin every 3 to 6
h (64), or by continuous intravenous infusion of regular
insulin at rates of 0.02 to 0.04 IU/kg body weight (1.4
to 2.8 IU/h in a 70-kg woman) (65). Capillary blood
sugar is measured every 1 to 4 hours (with periodic
measurements of plasma glucose for confirmation).
The glucose infusion may be delayed by 1 to 2 h when
hyperglycemia is present at entry, whereas insulin
administration may be withheld temporarily if the
blood glucose level is less than 3.9 mmol/L.
Elective cesarean section is scheduled early in the
morning when possible. Neither insulin nor glucose is
administered if the blood sugar level before the
procedure is between 3.9 and 7.8 mmol/L. Glucose,
insulin or both are given when blood sugar levels are
outside this range or the procedure is delayed
significantly.
Insulin requirements usually decline dramatically
immediately following delivery (often by 50% to 75%)
(31). The women who wish to breastfeed are
maintained at or above their antepartum caloric intake.
Because of the potential for oral agents to be secreted
in breast milk and cause hypoglycemia in the infant,
they are not prescribed for patients with type 2
diabetes if they wish to breastfeed. Those who do not
breastfeed are returned immediately to a diet
appropriate for nongravid women (30 to 32 kcal/ideal
body mass). All patients are encouraged to use the
diabetic management skills they have acquired during
gestation.
Gestational diabetes
Therapeutic goals are the same as in pregestational
diabetics. Insulin therapy is rarely required to maintain
intrapartum normoglycemia in women with GDM. The
vast majority of patients requiring insulin therapy
antepartum can discontinue it at delivery.
INTRAPARTUM DIABETIC
MANAGEMENT
The glucose utilization during labor in well controlled
diabetics is uniformly 2.55 mg/kg/min. The best
control achieved during pregnancy should not be lost at
labor. Plasma glucose should be monitored hourly and
maintained between 90 and 120 mg/dl (31).
MANAGEMENT OF GESTATIONAL
DIABETES MELLITUS
Pregnant women with GDM have higher perinatal
mortality, and they give birth to more macrosomic
newborns weighing >4 kg. Strict glycemic control of
GDM has been shown to decrease the proportion of
macrosomic newborns (>4000 g) (67). Managing
pregnant patients with GDM depends on obstetric
problems. Bed rest is the need in patients with habitual
abortion or preeclampsia. Hormonal therapy is needed
in a situation with incipient abortion, and cerclage of
uterine cervix is needed for incompetent internal
cervical os. The treatment of GDM is diet. Pregnant
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11.
patients who need bed rest require no more than 1800
kcal per day, and those who continue working require
2100 kcal per day (25-35 kcal/kg desirable body
weight). Insulin treatment is recommended when
fasting blood glucose is higher than 6.1 mmol/L, or
insulin >20 µU/L in amniotic fluid, in cases with
macrosomic fetus, placenta or polyhydramnios, and in
patients with glycosuria more than 2.0 mmol/L/24 h.
Shortacting insulin before each meal may be enough,
sometimes an intermediate acting insulin is added at
night. The insulin dosage usually increases as the
pregnancy progresses, particularly up to around 30
weeks of gestation. All women with GDM should have
ultrasound scan for fetal size and volume soon after the
diagnosis has been made; later they should have serial
scans every four weeks. During the last three weeks of
pregnancy it is important to monitor the fetus. Most
authors recommend labor induction at 38th week of
gestation, and all authors agree that pregnancy could
terminate before 40th week of gestation.
We prefer spontaneous vaginal delivery induced with
oxytocin infusion and amniotomy.
During labor it is important to monitor fetal heart rate
with cadiotocography. Before starting labor induction it
is important to check uterine cervix which has to be
ripe. When uterine cervix is not ripe, the delivery is
finished with cesarean section.
After delivery, the mother will not require further
insulin but blood glucose levels should be monitored
before leaving the hospital and OGTT should be
performed within six weeks. Women with diagnostic
OGTT for diabetes postpartum should be transferred
to a diabetic clinic. Those with normal glcuose or IGT
should be informed on the importance of attaining and
maintaining an ideal BMI through diet and on the
benefits of exercise. In any future pregnancy such a
woman should book early and undergo OGTT; if
normal, it should be repeated at 20-28 weeks of
gestation.
All women with GDM should receive nutritional
counseling by a registered dietitian when possible,
consistent with ADA recommendations.
Individualization of medical nutrition therapy (MNT)
depending on maternal weight and height is
recommended.
For obese women (BMI >30), a 30%-33% calorie
restriction (to –25 kcal/kg of actual weight per day) has
been shown to reduce hyperglycemia and plasma
triglycerides with no increase in ketonuria (68).
Restriction of carbohydrate to 35%-40% of calories has
been shown to decrease maternal glucose levels and to
improve maternal and fetal outcome (69).
Insulin is pharmacological therapy that has most
consistently been shown to reduce fetal morbidity
when added to MNT.
The measurement of fetal abdominal circumference
early in the third trimester can identify a large subset
of infants with no excess risk of macrosomia in the
absence of maternal insulin therapy. This approach has
been tested primarily in pregnancies with maternal
fasting serum glucose level <105 mg/dl (5.8 mmol/l).
Human insulin should be used when insulin is
prescribed.
Oral glucose-lowering agents have generally not been
recommended during pregnancy. However, one
randomized, unblinded clinical trial compared the use
of insulin and glyburide in women with GDM who were
not able to meet glycemic goals on MNT (70).
Programs of moderate physical exercise have been
shown to lower maternal glucose concentration in
women with GDM.
Breast-feeding, as always, should be encouraged in
women with GDM.
Longterm therapeutic considerations
Reclassification of maternal glycemic status should be
performed at least 6 weeks after delivery and according
to the guidelines from the Report of the Expert
Committee on the Diagnosis and Classification of
Diabetes Mellitus (71). Diagnostic criteria are shown
in Table 6.
141Diabetologia Croatica 31-3, 2002
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Table 6. Criteria for diagnosis of diabetes mellitus
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)GFI(ld/gm621<
ld/gm621>GPF
ld/gm041<GPh-2 ld/gm041>GPh-2
)TGI(ld/gm002<dna
ld/gm002>GPh-2
– – MDfosmotpmyS
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-necnocesoculg
ld/gm002>noitart

12.
Medications that worsen insulin resistance (e.g.,
glucocorticoids, nicotinic acid) should be avoided if
possible.
Education should also include the need for family
planning to ensure optimal glycemic regulation from
the start of any subsequent pregnancy. Low doses of
estrogen-progestogen oral contraceptives may be used
in women with prior histories of GDM, as long as no
medical contraindication exists.
MNT for diabetes has been proven to lower HbA1c
concentration by 1%-2% and is crucial for effective care
(72,73). MNT is recommended for the management of
GDM, and it is often the only diabetes treatment
offered to women with this condition.
FAMILY PLANNING IN DIABETES
MELLITUS
The timing of childbearing is an important question
in a diabetic woman. There are teenaged mothers on
the one hand and mothers in their late thirties or even
early forties on the other hand. In any, it is best to
conceive within ten years of the onset of diabetes,
before the development of vascular complications. It is
desirable that the planned child or children be born
from the first successful pregnancy or pregnancies of
the mother. Therefore, contraception before (and
between) the pregnancies is recommended.
In contraception, the advantage of barrier methods is
the virtual absence of adverse side effects. The
intrauterine device is safe and more comfortable, and
diabetics in good metabolic balance run no more risk of
complications than healthy women. Oral contra-
ceptives can be used safely in low doses in
uncomplicated diabetics (74). But since oral
contraceptives may increase blood pressure and
enhance platelet aggregation, they are not
recommended in cases of diabetes complicated by
angiopathy or other risk factors such as smoking,
hypertension, age (if over 35 years), etc. (68).
For patients in whom there is a medical reason against
pregnancy or who do not want to become pregnant
anymore, sterilization can be offered.
There is no medical reason against pregnancy in a
diabetic woman if she has no complications, no
additional disease, and her metabolic state is near
normoglycemic. In other cases, treatement of
accompanying disorders should be considered, and
pregnancy can only be recommended with caution
since it may carry a risk to maternal and fetal health.
This decision is obviously influenced by some
circumstances such as whether she is already pregnant
or only planning to have a child, if pregnant at an
appropriate age, and whether she already has a healthy
child. The decisions can be summarized as follows:
• pregnancy is not suitable or its continuation cannot
be recommended in the following cases:
- marked diabetic nephropathy, severe hyperten-
sion, pronounced albuminuria, reduced renal
function
- progressive therapy resistant proliferative
retinopathy impairing visual function
- severe ischemic heart disease
- severe diabetic ketoacidosis at the time of con-
ception or during the first week of gestation
(and only one subsequent pregnancy can be
recommended, after receiving preconceptional
care)
• pregnancy maintenance may be considered in case
of:
- pronounced hypertension, albuminuria
- advanced proliferative retinopathy threatening
vision
- demonstrable ischemic heart disease
- marked hyperglycemia, glycosuria, acetonuria
during the first weeks of pregnancy (a
subsequent pregnancy may be recommended
after preconceptional care)
- lack of cooperation
• no further pregnancy is recommended if the mother
with retinopathy has a healthy child and her
diabetes has existed for more than 20 years
DIABETIC PREGNANCY OUTCOMES IN
INDIA
India is a developing country with its own population
profile that is different from other countries. Although
the problems related to pregnancy outcomes in
diabetic women are the same throughout the world,
there are some economic and sociocultural conditions
that modify the severity of the problem from one part
of the world to the other. The level of literacy, different
economic status of the people, place of residence (rural
or urban), etc. influence the outcome of pregnancy in
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13.
diabetic women in India. Sixty-five percent of the
people live in rural areas lacking modern amenities of
life, communication, roads, rails and health care
facilities. In India, the inadequate budget for health
care precludes health departments from giving proper
and adequate attention to these patients. There are no
specialized clinics for diabetic pregnancies and no
health educators to explain the problems of diabetes in
pregnancy. Because of the highest rate of illiteracy in
Indian women, they do not show much interest to
understand the nature of their disease and its possible
impact on pregnancy. Even now some of the rural
women deliver at home by the help of a midwife or
sometimes even by the help of an elderly woman from
the household, which makes the outcome worse for
both the mother and the child, especially in diabetics.
Although preconceptional counseling is available at
medical teaching institutions, they are very few in
number and far from the reach of rural population.
Even when they are within reach in some areas to the
rural population, they do not utilize these services
because of their illiteracy. Home blood glucose
monitoring, which is the most important part in
diabetic pregnancy, is not carried out by nearly all
patients because of the high cost of the device. There
is no health insurance scheme in India which could
provide for these devices and the cost of treatment.
Although some private health insurance schemes are
coming up now, only the people from the upper middle
class (economically) can afford it. Nowadays, the
majority of people utilize the services of private
medical practitioners, where they are followed up in a
better way. However, poor people cannot even afford
the cost of consultations. Although private prac-
titioners provide a better medical care, they are poor in
record keeping, which is important in diabetic
pregnancy, especially in a gestational diabetic for the
future follow-up.
Ultrasound scan, which is most important in the
follow-up of fetal development and growth throughout
the gestational period, is not within reach of some of
rural population. Even when it is within reach, most of
these people cannot afford it because of poverty. Some
of those who can afford it are ignorant of its
importance.
In general, the pregnancy outcome in diabetic women
is poor in India when compared with the developed
world. The time has come for the government of India
to implement an effective plan to the benefit of
pregnant women with diabetes and those who develop
diabetes during pregnancy. Since India is a developing
country with many other problems in hand to deal with,
it can start this with a small budget. As the majority of
people live in rural India and since midwife is the
primary health care worker in rural India, the
government can start this program by educating
midwives on how to advise a pregnant diabetic. They
(midwives) must be able to recognize the high risk
group of pregnant women that are prone to develop
gestational diabetes, so that they can advise the patient
about the importance of antenatal checkup by an
obstetrician. Also, they (midwives) must be able to
teach an already diabetic patient about the importance
of preconceptional counseling by an obstetrician in
order to avoid maternal and fetal complications during
pregnancy. Also, they must follow up the patients after
delivery and advise them on the importance of diet and
exercise from time to time.
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